1. Field of Invention
The present invention relates to sliding material, more particularly the resin-based sliding material, in which polyimide or polyamide-imide is used as a binder.
2. Description of Related Arts
The heretofore generally used carbon (graphite) based sliding material is produced by using the phenol resin as a binder and by means of hot-pressing. In such sliding material, the phenol resin may be decomposed due to heat generation under high-speed condition or severe lubricating condition, since the heat-resistance of phenol resin is low.
Japanese Unexamined Patent Publication No. 52-44871 discloses resin-based sliding material consisting of from 30 to 70% by weight of binding component, i.e, polyimide resin, and from 30 to 70% by weight of polytetrafluoroethylene. This Japanese Unexamied Patent Publication also discloses the use of graphite as the lubricant. As an example of the composition containing graphite, 53% of polyimide, 1.5% of polyamide imide, 30% of polytetrafluoroethylene, and 2% of graphite is mentioned in this publication.
According to the investigations by the present inventors, the resin-based sliding material of Japanese Unexamined Patent Publication No. 52-44871 has poor wear-resistance under boundary lubricating condition and mixed lubricating condition.